Cisco Systems OL-14361-01 manual BGP Configuration Limits, 125

Chapter 5 Configuring Additional Router Features

Configuration Limiting

Maximum Routes Redistributed into OSPF: Example

In the following example, the maximum redistributed-prefixescommand is used to set the maximum routes redistributed into OSPF:

RP/0/RP1/CPU0:router# configure

RP/0/RP1/CPU0:router(config)# router ospf 100

RP/0/RP1/CPU0:router(config-router)# maximum redistributed-prefixes 12000

RP/0/RP1/CPU0:router(config-router)# end

Uncommitted changes found, commit them? [yes]: y

RP/0/RP1/CPU0:Mar 30 16:26:52 : config[65740]: %LIBTARCFG-6-COMMIT : Configuration committed by user 'cisco'. Use 'show configuration commit changes 1000000541' to view the changes.

RP/0/RP1/CPU0:Mar 30 16:26:52 : config[65740]: %SYS-5-CONFIG_I : Configured from console by cisco

RP/0/RP1/CPU0:router#

Number of Parallel Links (max-paths): Example

In the following example, the maximum paths command is used to set the maximum number of parallel routes:

RP/0/RP1/CPU0:router# configure

RP/0/RP1/CPU0:router(config)# router ospf 100

RP/0/RP1/CPU0:router(config-router)# maximum paths 10

RP/0/RP1/CPU0:router(config-router)# end

Uncommitted changes found, commit them? [yes]: y

RP/0/RP1/CPU0:Mar 30 18:05:13 : config[65740]: %LIBTARCFG-6-COMMIT : Configuration committed by user 'cisco'. Use 'show configuration commit changes 1000000542' to view the changes.

RP/0/RP1/CPU0:Mar 30 18:05:13 : config[65740]: %SYS-5-CONFIG_I : Configured from console by cisco

RP/0/RP1/CPU0:router#

BGP Configuration Limits

The maximum number of BGP neighbors (peers) that can be configured is 1024. This number cannot be changed through configuration. Any attempt to configure additional neighbors beyond the limit fails.

To prevent neighbors (peers) from flooding BGP with advertisements, a limit is placed on the number of prefixes that can be accepted from a peer for each supported address family.

You can override the default limits for an address family with the maximum-prefixcommand. Table 5-7summarizes the maximum configuration limits for BGP.

Table 5-7		BGP Configuration Limits and Commands
			Default	Absolute		Show Current Settings
			Maximum	Maximum	Configuration Command	Command
	Feature Limit Description		Limit	Limit	(Router Configuration Mode)	(EXEC Mode)
	Maximum number of neighbors		4000	15000	bgp maximum neighbor	None
	(peers)				limit
	IPv4 unicast maximum prefixes		524,288	4,294,967,	maximum-prefix n	show bgp neighbor IP_address
	that can be received from a			295
	neighbor
					Cisco IOS XR Getting Started Guide
	OL-14361-01						5-125